|
September 2000 Newsletter
Back to school-the ABC’s
Without the proper balance of vitamin A in the body, many problems
can occur. Eye disease is the foremost consequence of a vitamin A deficiency.
The three groups most affected by this deficiency are the elderly, teenagers,
and alcoholics.
Vitamin A is fat-soluble and is stored for long periods of time in
the liver. Because of this, there is a potential for toxicity. It is
very unlikely that a person would take in toxic levels through diet
alone.
Supplemental vitamin A is mostly used in the treatment and prevention
of vitamin deficiency and is widely known for its use in helping with
vision problems. Vitamin A has also been used in the treatment of asthma,
sebaceous cysts, fibrocystic breast disease, and premenstrual syndrome.
Good food sources of vitamin A include fish and liver oils, egg yolks,
and all milk products. Supplemental vitamin A is often made from cod
liver oil, synthetic vitamin A palmitate, and vitamin A acetate. Provitamin
A refers to about 50 compounds in a group of plant pigments called
carotenes. Provitamin A is converted to vitamin A in the body as it
is needed. Cooking does not damage the vitamin A content in food.
Beta carotene is absorbed into the walls of the intestinal lining
where it is converted into vitamin A as the body needs it.
Beta carotene also serves as an antioxidant, protecting the body against
free radicals and other harmful substances within the body that can
damage cells and tissues. It also has been shown to reduce the risk
of cardiovascular disease and multiple forms of cancer.
Beta carotene is an orange-colored pigment found in vegetables and
fruit, particularly dark leafy vegetables, broccoli, carrots, squash,
pumpkins, sweet potatoes, cantaloupe, apricots, and pink grapefruit.
Vitamin A necessity may increase in instances of trauma, fatigue, anxiety,
stress, smoking, and alcohol use.
In 1997, a study done in Spain suggested that low levels of vitamin
A may contribute to heart disease. Vitamin A levels were 25% lower in
cases of people with heart disease than in cases of people with no heart
disease.
The most commonly recommended dose of supplemental vitamin A is 10,000
IU.
References: Ruiz, R., et al. "Plasma levels of vitamins A and E
and the risk of acute myocardial infarction." Rv Cln Esp 197:6, 411-6,
1997.
The B-Vitamins
Vitamin B1
Also known as Thiamin, this was the first of the B Vitamins to be discovered
and is essential for almost every cellular reaction in the body. It is
involved in energy production and carbohydrate metabolism.
B1 is vital to the health of the nervous system, and helps prevent accumulation
of fatty deposits in arteries that slows the progression of atherosclerosis.
Foods rich in thiamin include dried beans, organ meats, peas, peanuts,
soybeans, and fish. The Recommended Daily Intake (RDI) is 1.5 mg per day.
Vitamin B2
Vitamin B2 is a yellow-orange, water soluble nutrient also called Riboflavin.
It is vital for the normal reproduction, growth, repair, and development
of skin, hair, nails, and connective tissue. Recent research shows that
B2 may be helpful in reducing migraines.
It is found in organ meats, milk, yeast, fish, eggs, and dark leafy
vegetables and has an RDI of 1.7 mg daily.
Vitamin B3
This vitamin, more commonly known as Niacin, is more resistant to heat
and other damage than the other B vitamins. It has been clinically proven
to help treat high cholesterol and has other cardiovascular functions.
It has also been used to treat anxiety disorders and circulatory problems.
Taking too much niacin with an empty stomach may result in a niacin-flush-a
somewhat harmless but intense reaction that causes a heat flushed feeling
with redness in the face and neck which lasts from 15 to 30 minutes. For
this reason some will prefer using the niacinamide form which does not
cause the flushing action.
The RDI is 20 mg per day with rich sources including beef, fish, milk,
cheese, whole wheat, corn, and carrots.
Vitamin B6
Vitamin B6 or Pyridoxine is necessary for the proper functioning of
over 60 enzymes, and in the synthesis and breakdown of amino acids, in
the conversion of amino acids to carbohydrates or fat and in the conversion
to one type of fat to another.
Vitamin B6 deficiencies are most commonly found in adolescents, the elderly,
those on restricted diets, and alcoholics. Vitamin B6 is found in chicken,
fish, eggs, wheat germ, and brewer’s yeast. The RDI is 2 mg.
Vitamin B12
B12, also known as Cobalamin, is the only vitamin that contains the essential
mineral cobalt. This vitamin is essential for the metabolism of nerve
tissue, fats, and carbohydrates, the synthesis of proteins, and for the
health of the entire nervous system.
Vitamin B12 deficiency disease is called pernicious anemia and is often
accompanied by weight loss, weakness, pale skin, and psychological disturbances.
It can be found in crabs, oysters, eggs, milk, and meat. Only small
amounts are required with an RDI of 10-20 mcg per day.
Other B Vitamins
The other vitamins in the vitamin B family include biotin, choline,
folic acid, inositol, and para-aminobenzoic acid (PABA).
Biotin supports healthy bone marrow, nerve tissue, hair, and skin.
Choline assists in fat and cholesterol metabolism and it minimizes excess
fat in the liver.
Inositol is vital for hair growth and fat and cholesterol metabolism.
Folic acid is critical in the prevention of spinal birth defects. Pregnant
women are urged to eat specially fortified foods or take supplements of
800 mcg daily to protect against spina bifida.
PABA is important for its nourishment of the hair, its stimulation of
cell growth and tissue repair.
References: Haas, E. Staying Healthy with Nutrition: The Complete
Guide to Diet and Nutritional Medicine, 1992.
Vitamin C
In 1928 Vitamin C was discovered and was shown to be the leading nutrient
in preventing and curing scurvy, a disease that caused death to numerous
seaman. Since then is has been found to be involved in hundreds of vital
processes.
It is helpful in the prevention of the common cold and flu and is involved
in antibody production, helping the function and activity of white blood
cells. Vitamin C aides in the production of interferon-antiviral and anticancer
substances.
Vitamin C helps maintain collagen in the body, which is responsible
for making skin, bones, teeth, and connective tissues strong. It helps
in the creation of neurotransmitters and Carnitine, a substance necessary
for the production of energy from fatty acids in the cells.
Many benefits of combining Vitamin C and Vitamin E have been shown as
they work synergistically to extend antioxidant activity.
Vitamin C is found in citrus fruits, strawberries, currents, papaya,
red peppers, and broccoli. The RDI is 70-95 mg, however overall recommendations
vary greatly from 100 mg to 5,000 mg per day. Symptoms of a Vitamin C
deficiency are bleeding, reddening and bleeding of the gums, loose teeth,
joint pain, dry, scaly skin, and blood vessel damage.
In 1996, a study published in the American Journal of Epidemiology showed
that low levels of Vitamin C have been linked to an increased risk in
cardiovascular disease.
Reference: Ness, A.R., et al. "Vitamin C status and serum lipids."
European Journal of Clinical Nutrition 50:11, 724-9, 1996.
Vitamin D
Vitamin D is formed in the skin of animals and humans by the action of
short-wave ultraviolet light, the so-called fast-tanning sun rays.
Fat-soluble vitamin D supplements are available in two forms. Vitamin
D3 is believed to exhibit the most potent cancer-inhibiting properties
and is the preferred form of the vitamin.
The list of vitamin-D-rich foods includes egg yolks, butter, cod liver
oil, and cold-water fish such as salmon, herring, and mackerel.
Evidence of vitamin D’s protective effect against cancer is compelling.
This vitamin also has an important relationship with calcium. Supplemental
vitamin D has been shown to reduce hip fracture risk among elderly women
when combined with supplemental calcium. In one study of 3,270 healthy
women, 1,634 received 1.2 grams of vitamin D3, while the other 1,636 received
a placebo. During the 18-month study, the supplemented group experienced
43% fewer hip fractures, 32% fewer non-vertebral fractures, and 2.7% increase
in bone density of the proximal femur compared to the 4.6% bone density
decrease seen in the placebo group.
Unfortunately, not everyone is getting enough vitamin D. A recent study
reveals that about 10% of retirees in Boston social clubs are vitamin-D
deficient.
A recent study showed that 37% of adult hospital patients were deficient
in vitamin D upon admission.
The U.S. Recommended Dietary Allowance (RDA) of vitamin D is 200 IU.
Reference: Grimes D.S., et al. "Sunlight, cholesterol and coronary
heart disease." QJ Med 1996;89:579-89.
Vitamin E
Vitamin E is a fat-soluble vitamin that is most significantly found in
the lipids of cell membranes and in circulating low-density lipoproteins.
It is able to become localized in cell membranes, and, as free radical
formation occurs, vitamin E "quenches" free radicals before they damage
cellular structures.
Researchers continue to find evidence that vitamin E’s antioxidant activity
reduces the risk of heart disease and cancer. Two epidemiological studies
published in the New England Journal of Medicine show that both men and
women who supplement with at least 100 IU of vitamin E per day for at
least two years have a 37% to 41% decrease in the risk of heart disease.
In a highly publicized clinical trial, the Cambridge Heart Antioxidant
Study, vitamin E supplementation of 400 or 800 IU per day decreased the
risk of non-fatal heart attack in a double-blind, placebo-controlled trial
of 2,002 patients with coronary disease who were treated with vitamin
E or placebo and followed for 510 days.
Because vitamin E improves heart and muscle respiration, it may help
improve stamina and endurance. In a study of 20 women between the ages
42 and 64, more than 50% of the women treated with vitamin E-containing
cream concluded that topical vitamin E induces smoothing of fine lines
and wrinkles in sensitive areas of the face.
Vitamin E is naturally found in wheat germ oil, nuts, seeds, vegetable
oils, whole grains, egg yolks, and leafy green vegetables.
The most commonly recommended dose of supplemental vitamin E is 400 IU.
However, people with high blood pressure or who take blood-thinning or
anticlotting drugs should consult with a physician before taking supplemental
vitamin E.
References: Stephens, N., et al. "Randomized controlled trial of vitamin
E in patients with coronary heart disease." The Lancet 347:781-6, 1996.
Health Tip
In a review article in the Journal of Family Practice, echinacea was
found to reduce intensity and duration of symptoms when used at the earliest
onset of colds.
The review of clinical studies provides additional support for the therapeutic
benefits of echinacea as an early defense for upper respiratory infections.
Patients began treatment at the first signs of infection. Treatment
continued for eight days. Patients taking echinacea reported fewer instances
of "full blown" colds than those receiving a placebo.
Reference: Journal of Family Practice, Aug. 1999.
|
